#include <stdio.h>

int main()
{
    int x = 30;            // 原始的 x

    printf("x in outer block: %d at %p\n", x, &x);
    {
        int x = 77;        // 新的 x，隐藏了原始的 x
        printf("x in inner block: %d at %p\n", x, &x);
    }
    printf("x in outer block: %d at %p\n", x, &x);
    while (x++ < 33)        //原始的 x
    {
        int x = 100;        //新的 x, 隐藏了原始的 x
        x++;
        printf("x in while loop: %d at %p\n", x, &x);
    }
    printf("x in outer block: %d at %p\n", x, &x);
    
    return 0;
}